Nipple illuminator for photodynamic therapy

ABSTRACT

A device for delivering phototherapeutic light to the nipple and surrounding tissue of a breast. Many mastectomy procedures for patients with breast cancer require removal of the nipple. Thus, for the best aesthetic result, post-operative augmentation or reconstruction of the breast includes the implantation of an artificial nipple. The present device and method permits a more conservative mastectomy to be performed while reducing the risk of recurrence wherein cancerous and pre-cancerous tissue in the nipple and surrounding aureole tissue are treated by illuminating the tissue with phototherapeutic light. The tissue is first perfused with a photosensitizer which accumulates therewithin. An embodiment of the device, which includes a rigid or semi-rigid hemispherical shell for structural stability, is attached to the breast. The device includes a transparent flexible aperture which is designed to fit snugly against the outer surface of the nipple and surrounding tissue. Phototherapeutic light from a light source enters the shell by means of a fiber optic and is conducted to a light diffuser tip disposed within the shell in optical communication with the light output end of the fiber optic. The light emanating from the diffuser tip is reflected from the interior surface of the hemispherical shell to uniformly illuminate the nipple and surrounding photosensitizer-laden tissue. In another embodiment a tissue expander is implanted within the breast following mastectomy. The tissue expander is adapted to receive light from a light source via a fiber optic and deliver diffuse phototherapeutic illumination to the tissue adjacent to and surrounding the tissue expander.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a light delivery device for uniformlyilluminating the nipple and surrounding tissue of a breast.

2. Prior Art

Ductile carcinoma in situ (DCIS) is the most common form of breastcancer. The treatment of choice for DCIS depends upon the stage ofgrowth of the tumor. For small tumors, that is, tumors less than 1 or 2centimeters in diameter, a lumpectomy followed by radiation treatment tothe affected breast is conventional. If there is more extensiveinvolvement and/or there is an invasive component present it may bepreferable to perform a mastectomy. A conventional mastectomy, when DCISis present includes the removal of the nipple. The reason for this isthat much of the pre-cancerous cell are contained within the milk ductsof the breast. Since the nipple area is rich in milk ducts, it isprudent to remove the entire nipple.

The use of photodynamic therapy for treating breast cancer has beenrestricted due to the limited ability of light to penetrate tissue.Whole breast illumination is not practical at present because a dosageof phototherapeutic light having a wavelength suitable for administeringphotodynamic therapy only penetrates to an extent to about 1 centimeterin depth. Thus, the conventional mastectomy is the most commonlyemployed procedure for treating advanced stages of DCIS. In addition,even with nipple excision, some tissue remains behind following amastectomy, adhering to the overlying skin, which tissue may includecancerous or precancerous cells.

If it were possible to provide a more conservative approach by savingthe nipple, this would facilitate reconstruction of the breast andprovide the patient with a superior appearance following surgery. Thus,there is a need for a method for treating patients presenting with DCISby employing photodynamic therapy to the nipple and surrounding tissueto destroy cancer cells which will enable a mastectomy to be performedwithout the necessity of removing the nipple while minimizing the riskof recurrence.

SUMMARY OF THE INVENTION

It is an object of this invention to provide a device for deliveringillumination uniformly to the nipple and the surrounding tissue of apatient with DCIS in a therapeutically effective dosage of light.

It is another object of this invention to provide a method fordestroying cancer and pre-cancerous cells in the nipple and surroundingtissue of the breast.

It is a further object of this invention to provide a tissue expanderfor temporary implantation within the breast which can be used foradministering photodynamic therapy to the surrounding tissue.

The features of the invention believed to be novel are set forth withparticularity in the appended claims. However, the invention itself bothas to organization and method of operation together with further objectsand advantages thereof may best be understood by reference to thefollowing description taken in conjunction the accompanying drawings inwhich:

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross sectional schematic view of a first preferredembodiment of a light delivery device in accordance with the presentinvention adapted for illuminating the nipple and surrounding tissue ofa human breast.

FIG. 2 is a schematic drawing of a second preferred embodiment of alight delivery device suitable for illuminating the nipple andsurrounding tissue of the breast wherein a light scattering medium isincluded within the interior of the device to provide more diffuseillumination at the output aperture.

FIG. 3 is a third preferred embodiment of the device of the presentinvention wherein a pair of identical devices is used to uniformlyilluminate the nipple and surrounding tissue of both breasts.

FIG. 4 is an elevational cross-sectional view of an inflatable tissueexpander device adapted to receive phototherapeutic light from a lightsource and deliver the light diffusely to the surrounding tissue.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning now to FIG. 1, a first preferred embodiment of the devicesuitable for illuminating the nipple and surrounding tissue of a breastto a depth of about 1 cm below the skin surface is shown at 10. Thedevice 10 comprises an outer, substantially hemispherical shell 11 of arigid or semi-rigid material having an inner reflective surface 12coating the interior surface thereof A fiber optic 13 conducts lightfrom a light source 14 through an optical connector feedthrough 15 toilluminate a convex reflector 16 in optical communication therewith. Atransparent silicone membrane 17 having an indentation 17c, pre-formedto conform to the shape of a portion of a human breast comprising thenipple 17b, encloses the open end of the hemispherical shell 11 andforms the light output aperture of the device. The convex reflector 16is attached to the feed through 15 by means of a rigid transparent bulb15a and disposed adjacent to the flexible transparent membrane 17 at theapex portion of the device where the tip of the nipple 17b will beplaced. The spherical bulb 16a, in rigid attachment to the convexreflector 16 and the fiber optic feedthrough 15, keeps the light outputend 19 of the fiber optic 13 in optical alignment with the optic axis A(FIG. 2) of the hemispherical reflector 16 and fiber optic 13. Theinterior volume 20 of the device 10, which interior volume 20 isenclosed by the shell 11 and the transparent membrane 17, contains anoptically transparent fluid such as water or a low viscosity deformablegel such as silicone gel or hydrogel. Phototherapeutic light from alight source 14 is conducted via the fiber optic 13 to the light outputend 19 where it emerges to impinge upon the convex reflector 16. Thelight is reflected from the surface of the convex reflector 16 toimpinge upon the reflective inner surface 12 of the shell 11 where thelight is re-reflected and exits the interior volume 20 through theaperture provided by the transparent membrane 17 and enters the skin.

FIG. 2 shows a second preferred embodiment of a device in accordancewith the present invention which is similar to the embodiment of FIG. 1.The fiber optic 13 has a light output terminus 22 comprising a sphericaldiffuser tip. The interior cavity within the shell is filled with atransparent medium having optically scattering centers 21 dispersedtherethroughout light emanating from the diffuser tip 22 sphericallyilluminates the interior portion of the shell and reflects off thereflective inner surface 12 and is directed toward the nipple and thesurrounding tissue. The apex of the nipple 17b is placed within theconforming curvature of the recess 17c molded into transparent membrane17 in snug engagement therewith. Flexible lugs 18 projecting laterallyfrom the shell 11 provide means for attaching the devices to each other(if more than one is used as shown in FIG. 3) and/or to the body of apatient.

A third preferred embodiment of the device of the present invention isshown at 10a in FIG. 3. In FIG. 3, two identical nipple illuminatordevices 10a are connected by means of an adjustable connecting strap 32.The outer lug 18 on one end of the device engages the adjustable strap31 attached to the outer lug 18 on the other light delivery device toenable the user to fasten the device around the chest. Depending on thecondition of the breasts (i.e. the presence of bilateral cancer) one orboth devices may be illuminated. A light source may be employed which isin optical communication with both devices and which can be attached tothe body for wearing.

The device may be used to illuminate the breast in the following manner.A suitable photodynamically active photosensitizing agent such as, forexample, tinethyletiopurpurin or a hematoporphyrin derivative isinjected into the patient and allowed to perfuse the breast where itwill accumulate within the cancerous and pre-cancerous tissue (targettissues) of the breast. After a suitable period of time has elapsed topermit accumulation of the photosensitizer within the target tissue, thedevice is attached to the breast such that the nipple 17b and thesurrounding aureole tissue 17a are pressed against the transparentmembrane 17 of the device with the nipple centered within the recess17c. The device 10 is affixed to the chest wall by means of flexiblelugs 18 which may be taped to the chest or connected to one another bymeans of a strap which extends around the chest of the patient. A lightsource 14 is activated to provide phototherapeutic light which isconducted to diffuser tip 22 by means of fiber optic 13 to illuminatethe interior of the device(s). A pickup fiber (not shown) may be used tomonitor the dosage of phototherapeutic light actually delivered to thetissue. After a sufficient dosage of light has been administered toeffect therapy, the light source is disconnected and the device removedfrom the breast. The above procedure may be used either before or afterthe mastectomy. The foregoing method provides means for conserving thenipple and surround tissue during a mastectomy while minimizing thepatient's risk of recurrence.

PDT may also be employed post-operatively to treat any remaining tissuescontaining DCIS which are attached to the skin following partial ortotal removal of breast tissue. A tissue expander device may be placedbeneath the skin and disposed within the pocket remaining followingmastectomy. Tissue expander devices are well known in the art. Examplesof such devices are shown in U.S. Pat. Nos. 4,841,948 to Bauer et. al.and U.S. Pat. No. 4,671,255 to Dubrul et. al. The inflatable portion ofthe device is implanted beneath the skin within the dissected cavitywhere tissue has been removed, and slowly inflated. The overlying skinstretches to accommodate the increasing volume of the tissue expander.Inflation fluid is introduced by transdermal injection into a fill port.The fill port is implant to underlie an accessible portion of thepatient's skin. The fill port may be integral with the tissue expanderas shown in U.S. Pat. No. 4,671,255 or connected to the inflatable shellby a fill tube as shown in U.S. Pat. No. 4,841,948. In any event, thefill port is self-sealing to the track of a needle or cannula insertedtherein. Other self-sealing fill valves suitable for use with a bluntcannula are described in U.S. Pat. Nos. 4,178,643, 5,084,061 and5,127,627.

An inflatable tissue expander device suitable for implantation beneaththe skin and adapted to deliver phototherapeutic light to thesurrounding tissue is shown in elevational cross-section in FIG. 4. Thetransparent shell 41 of the tissue expander 40 is adapted to transmit aportion of the phototherapeutic light incident thereon emanating from alight diffuser element 42 disposed within the interior of the shell. Aportion of the light is reflected inwardly to be re-reflected outward.The shell 41 is inflated with an inflation fluid 43 containing lightscatterers 44 dispersed therein such as Teflon spheres or silica untilthe desired volume is achieved. A photosensitizer suitable forperforming photodynamic therapy is then injected intravenously into thepatient and permitted to accumulate within any residual cancerous tissue45 remaining following surgical mastectomy. Light is conducted to thediffuser element 42 disposed within the interior of the tissue expanderby a fiber optic 46. The light emitted by the diffuser element 42 isscattered by the inflation medium 43 prior to impinging on the shellthereby further diffusing the light. A portion of the scattered lightincident upon the inner surface 47 of the shell 41 is transmittedtherethrough to diffusely illuminate the tissue surrounding the tissueexpander including the muscles overlying the chest wall. The correctdosage of light required to effect photodynamic therapy of diseasedtissue is then administered.

A fiber optic, such as described in U.S. Pat. Nos. 5,196,005 and5,237,638, may conveniently be inserted through a cannula guide into theinjection port or valve and into the interior of a tissue expander toconduct light to a diffuser tip disposed in the interior thereof. Apartially reflective coating such as gold or silver on the inner surfaceof the tissue expander promotes multiple reflections of treatment lightwithin the interior of the expander thereby facilitating more uniformdelivery of light to the surrounding tissue.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. For example, thehemispherical shell 11 may include a soft, flexible peripheral flangearound the perimeter thereof which conforms to surface contours of theskin. It is therefore intended to cover in the appended claims all suchchanges and modifications that are within the scope of this invention.

What I claim is:
 1. A light delivery device adapted for uniformlyilluminating a nipple and surrounding tissue of a breast withphototherapeutic light from a light source comprising a hemisphericaloptically opaque shell having: (a) a reflective inner surface and havinga fiber optic connector means projecting thereinto, said fiber opticconnector means having a diffuser tip at a distal end and (b) anoptically transparent elastomeric film attached thereto to provide alight output aperture for delivery of light from said diffuser tipexciting said hemispherical shell, said optically transparentelastomeric film being pre-molded to substantially conform to the shapeof the nipple.
 2. The device of claim 1 wherein said opticallytransparent elastomeric film is elastically deformable.
 3. The device ofclaim 1 wherein said hemispherical shell and said film define a cavityand wherein an optically transparent fluid substantially fills saidcavity.
 4. The device of claim 2 wherein said hemispherical shell andsaid film define a cavity and wherein an optically transparent fluidsubstantially fills said cavity.
 5. The device of claim 3 wherein saidfluid has light scattering centers dispersed therein.
 6. The device ofclaim 4 wherein said fluid has light scattering centers dispersedtherein.